This invention generally relates to a fuel injector for an internal combustion engine. More particularly, this invention relates to a fuel injector with an active closing needle valve.
A fuel injection system includes a fuel rail that communicates fuel to a plurality of fuel injectors. In some applications the fuel injector does not include a control piston and therefore does not have a steady leakage that is advantageous for diesel engine applications. Without a separate control piston, the fuel injector does not close as quickly as desired. A needle valve within the fuel injector closes by way of a biasing spring that closes once fuel pressure drops below a determined pressure. Common fuel injectors include a throttle valve that supports the closing process. The use of a throttle valve reduces injection pressure. However, it is desirable to increase fuel injection pressures to increase performance and fuel efficiency.
Accordingly, it is desirable to develop and design a fuel injector that provides the desired opening and closing time without reducing injection pressure.